Location and positioning systems are increasingly being used to determine locations of various network devices, such as mobile cellular phones and global positioning systems (GPS) devices. Moreover, information concerning the geographic location of a network node may be useful for any number of reasons, including verifying network paths through the network node, customized content delivery, and combating fraud. A part of networking research is geared towards developing systems and technologies that can help to automatically locate people and equipment. Many such systems and technologies have been developed over the years; because each such approach solves different problems or supports different applications, they vary widely in many parameters, such as physical phenomena used for location determinations, form factors of sensing apparatus, use of infrastructure and portable elements, and resolution in time and space.